So sánh phương pháp

	Danh mục Tạp chí Truy cập Mở	Chỉ số Tác động của Tạp chí	PubMed và MEDLINE	Cơ sở dữ liệu Scopus	Ulrichsweb Global Serials Directory
Lĩnh vực	Trắc lượng thư mục	Trắc lượng thư mục	Trắc lượng thư mục	Trắc lượng thư mục	Trắc lượng thư mục
Họ	Process / pipeline	Process / pipeline	Process / pipeline	Process / pipeline	Process / pipeline
Năm ra đời	2003	1955	1966	2004	1932
Người khởi xướng	DOAJ Community (Swedish library consortium, later expanded to international consortium)	Eugene Garfield, Institute for Scientific Information (ISI)	National Library of Medicine (NLM), U.S. National Institutes of Health	Elsevier	Bowker (originally R.R. Bowker), now ProQuest LLC
Loại	Database	Metric	Database	Database	Database
Công trình gốc	Directory of Open Access Journals. (2024). About DOAJ. Retrieved from https://doaj.org/	Garfield, E. (1972). Citation analysis as a tool in journal evaluation. Science, 178(4060), 471-479.	National Library of Medicine. (2024). PubMed: Home. Retrieved from https://pubmed.ncbi.nlm.nih.gov/	Elsevier. (2024). Scopus: The largest abstract and citation database of peer-reviewed literature. Retrieved from https://www.elsevier.com/products/scopus	ProQuest. (2024). Ulrichsweb: Global Serials Directory. Retrieved from https://ulrichsweb.serialssolutions.com/
Tên gọi khác	DOAJ, Directory of Open Access	IF, JIF, Impact Factor, 2-year Impact Factor	PubMed, MEDLINE, NLM, PubMed Central	Scopus, Elsevier Scopus	Ulrichsweb, Ulrich's International Periodicals Directory, Ulrich's Directory
Liên quan	5	5	5	5	4
Tóm tắt	The Directory of Open Access Journals (DOAJ) is a community-maintained, freely accessible directory of high-quality, peer-reviewed open-access journals and articles established in 2003. DOAJ indexes over 20,000 open-access journals across all disciplines (sciences, social sciences, humanities, arts) from diverse geographic regions. The directory serves researchers, librarians, and administrators as the authoritative curated list of legitimate open-access journals—differentiating quality open-access publications from predatory journals that lack genuine peer review. DOAJ quality seal, awarded to journals meeting stricter governance and transparency criteria, enables identification of the highest-caliber open-access publications.	Journal Impact Factor (JIF) is a metric developed by Eugene Garfield in 1955 and published annually by Clarivate Analytics through Journal Citation Reports (JCR). It measures the average citation frequency of articles published in a journal over a two-year window, serving as a proxy for journal prestige and influence. A journal's Impact Factor equals the number of citations received in year Y to articles published in Y-1 and Y-2, divided by the number of citable items published in that same window. Despite widespread adoption in research evaluation, Impact Factor has significant limitations and critics argue it conflates journal prestige with article quality.	PubMed is a free, publicly accessible literature database maintained by the National Library of Medicine (NLM), a division of the U.S. National Institutes of Health. It provides access to biomedical and life sciences literature from MEDLINE (the curated subset of ~30 million indexed journal articles), life science journals, in-process articles, and preprints. MEDLINE, established in 1966, is the gold standard for biomedical literature indexing, using MeSH (Medical Subject Headings), a hierarchical controlled vocabulary of ~33,000 terms. PubMed is the primary discovery tool for clinicians, researchers, and healthcare professionals worldwide seeking evidence-based information.	Scopus, owned by Elsevier, is the world's largest abstract and citation database covering peer-reviewed journals, conference proceedings, and book chapters across all scientific disciplines. Launched in 2004, Scopus now indexes over 37 million documents from more than 6,500 journals, with expanded coverage of open-access publications and emerging regional journals. Scopus provides researchers and institutions with comprehensive citation tracking, field-normalized impact metrics (CiteScore, SJR, SNIP), and analytical tools for literature discovery, research evaluation, and institutional benchmarking.	Ulrichsweb is a comprehensive, subscription-based global serials directory cataloging over 300,000 print and electronic journals, magazines, newspapers, and other periodical publications. Developed by ProQuest (originally R.R. Bowker), Ulrichsweb has served librarians and researchers for over 90 years as the authoritative source for journal metadata, publication information, and peer-review verification. A unique feature is Ulrichsweb's verification program: editorial staff contact journals directly to confirm peer-review claims, marking journals as 'refereed' only after validation. This verification process distinguishes legitimate peer-reviewed journals from predatory publishers falsely claiming peer review.